During cataclysm the dungeon system was changed to allow players to queue for dungeons/heroics, so that the first seven times we cleared it we got the extra rewards. Allowing players that don’t have enough time to log on each day to queue and knock them all out over a weekend etc.

You now get Valor with every run, with a bonus for the first of the day. It's similar to the rested XP bonus while leveling up. We wanted a better catch up mechanism. More folks did dungeons/heroics when we had one a day than seven a week. The latter felt too much like a job.